This invention relates generally to automobile electrical systems and, more particularly, to electrical junction boxes for housing some of the components of automobile electrical systems, such as fuses and relays.
Automobile electrical systems typically include a large number of electrical subsystems, such as lighting and signaling, instrumentation, and engine control. These subsystems are generally interconnected by networks of wires and cables, which run throughout the vehicle. Each of these electrical subsystems includes numerous electrical components, such as fuses, relays and connectors. In some automobiles, the fuses and relays are distributed throughout the vehicle, while in others the wires and cables are routed through a single, centrally-located electrical junction box, which houses most or all of the fuses and relays in the vehicle.
A typical "central" electrical junction box includes a housing and an array of male and female electrical connectors supported by the housing. Generally, one side of the housing supports the female electrical connectors and the opposite side of the housing supports the male electrical connectors. The female electrical connectors receive the fuses and relays, while the male electrical connectors receive electrical connectors from the various electrical subsystems of the automobile. The male and female electrical connectors are internally connected within the junction box by a maze of copper-alloy ribbons. The ribbons are stamped from a sheet of copper-alloy metal and then bent at precise angles to provide the proper routing of the ribbons through the interior of the electrical junction box.
An electrical junction box of this type is generally durable and maintenance-free during use, but is difficult to manufacture and redesign. Also, this type of electrical junction box is rather expensive because an excessive amount of copper is generally required to fabricate the ribbons. Accordingly, those skilled in the art have sought to improve upon the design of this type of electrical junction box. For example, United Kingdom Patent No. 2 022 333 discloses an automobile electrical junction box in which several circuit boards are bonded to a rigid carrier base. Each circuit board includes a sheet of copper that is bonded to a sheet of flexible insulating material, preferably with double-sided adhesive tape. The sheet of copper is then etched to form circuit strips. Some of the circuit strips have metal tabs protruding from the edges of the insulating material. These metal tabs are bent so that they extend in a direction generally perpendicular to the circuit boards, to form male electrical connectors. The male electrical connectors receive electrical connectors from the electrical subsystems of the automobile. High current distribution is afforded by a bus bar disposed under the carrier base.
U.S. Pat. No. 4,555,638 to Lobe discloses an automobile electrical junction box having a single printed circuit board. The printed circuit board has a first row of female electrical connectors positioned along an edge of the circuit board. A second row of female electrical connectors, supported by the junction box housing, is positioned adjacent the first row of connectors. The first row of female electrical connectors makes electrical contact with the traces on the circuit board and the second row of female electrical connectors receives electrical connectors from the electrical subsystems of the automobile. The two rows of female electrical connectors form pairs of electrical connectors, which receive fuses for completing the circuits between the traces on the circuit board and the electrical subsystems of the vehicle. High current distribution is afforded by a bus bar disposed under the circuit board.
These types of electrical junction boxes are also rather expensive because an excessive amount of copper is generally required to fabricate the circuit boards. Each circuit board is typically clad with the thickness of copper that is required for the highest current signal that is to be conducted by the circuit board. Unfortunately, such copper layers are then unnecessarily thick for most of the other signals that are to be conducted by the circuit board. One possible solution to this problem is to utilize bus bars for carrying the high current signals. However, a large number of high current signals are typically carried by an electrical junction box and, therefore, a large number of bus bars would be required, thus complicating the manufacturing process of the box. Accordingly, it has become apparent that a new approach to the construction of electrical junction boxes is needed. The present invention is directed to these ends.